Boss EH-2 Enhancer Mods?

[zacharybroyles]

http://www.diystompboxes.com/cgi-bin/webbbs_scripts/webbbs_config.pl?noframes;read=167

I found that, anyone know any mods for that pedal
I guess i could replace the 1uf electro caps for metal film anything else i dont really know what to do
any ideas?

[Mark Hammer]

I'm not intimately familiar with this particular pedal, but my experience is that people generally expect too much from pedals of this category.  Although they do it in different ways, the general principle is that they isolate the mid-to-upper harmonics, boost them in one of a variety of ways that result in more than just the SAME harmonics being louder, and then mix the additional harmonic content back in with the original clean signal.

There are essentially 2 kinds of parameters to juggle in such pedals, some of which may already be adequately taken care of:

1) Where the dividing line is between harmonic that get additional processing and everything else.  Some pedals include a variable highpass filter intended to anticipate the magical dividing line between the harmonics of interest and everything else, and how it shifts depending on the instrument (e.g., acoustic guitar may be different than bass or cymbals).  I doubt that Boss would make a pedal that was TOO focussed in the range of cutoff frequencies available, but you may have exotic tastes.

2) The gain/boost of the side-processing subcircuit.  Usually, there is some sort of disortion circuit that is part of the sidechain. As you probably know, you can't always get fuzz from a fuzz pedal; the signal you feed it has to be strong enough, and the pedal has to apply enough gain to turn a normal signal *into* fuzz.  As the filter cutoff is changed, because of the normal/natural difference in amplitude of different harmonics, you can end up feeding the pedal with an insufficiently hot signal to produce the needed harmonic distortion.  This is the long way of saying that it is possible the pedal is not sensitive enough to YOUR signal and YOUR filtering needs.

One area where people's expectations tend to be unrealistic is in terms of how clean and crisp the input signal needs to be for the pedal to appear to be functioning properly.  ALL "exciter" type pedals need a hot wide-bandwidth hiss-free input signal.  If you do anything that results in giving it hiss to boost, or results in giving it insufficient high end to boost for mixing-in purposes, the pedal will appear to do nothing.

A second area where their expectations are unrealistic is in the kind of signal chain and rig needed to hear what the pedal has done.  In many instances, you'll need either a tweeter or a speaker complement with a similar range (e.g., full-range speakers that go out to 10khz or more) to hear the difference.  You will also need to pay attention to any treble loss between EH-2 and speakers resulting from cable capacitance, tone settings, or loading down by insufficient input impedances.

In short, one of the best mods you can do to thispedal is to pay attention to your guitar.  I might suggest sticking a FET buffer in the guitar or making one of those built-into-the-phone-jack FET buffers shown on Don Tillman's site.  I would also suggest using a single-coil equipped instrument if you aren't doing so already.

This is one of those deals analogous to expecting a sub-woofer to make a difference when Neil Young is singing.  If the input signal doesn't contain what you need, then it doesn't matter how many opportunities you provide to "boost" it.

[stm]

It would be nice to have a look at the schematic. So far I've been able to collect over 30 Boss schems during these years, however the EH-2 still eludes me.

It would be nice to be able to compare it with the SP-1 Spectrum, which is basically a dedicated kind of equalizer with no gain/distortion/harmonic-generating networks, and no level-dependent gain control and time constants.

[Mark Hammer]

If you haven't seen it yet, do a google search on the Harmonic Sweetener from Jules Ryckebusch.  It's posted on a bunch of different sites.  What you will see is R.G.'s drawing of what I did with the original.  Only two real changes: variable gain and variable filter frequency.  Ironically, you won't find the original, although I managed to buy the EM back issue that had the article if anyone needs it.

[TheBigMan]

What Mark says is very true.  The EH-2 is a useful pedal in it's own way, but very rig dependent.  I keep meaning to trace it out, if I get my scanner working I'll post some images.

[zacharybroyles]

I likethe eh-2 just never use it and if I could mod it to make it better, then whats wrong with that

[Jaicen_solo]

Well, how do you want it to be better? Quiter operation? True bypass?
It helps not to be vague in these situations, do you have a particular problem with what the pedal is doing to your signal??